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Finding the Fourth Proportional to 877.91, 1,211.99 and 641.61

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Solution

The fourth proportional to 877.91, 1,211.99 and 641.61 is: 885.77

Step by Step Solution

  1. Step 1: Write the proportion equation
    877.91 : 1,211.99 = 641.61 : x
  2. Step 2: Convert to fraction form
    877.91/1,211.99 = 641.61/x
  3. Step 3: Cross multiply
    877.91x = 1,211.99 × 641.61
  4. Step 4: Simplify right side
    877.91x = 777,621.70
  5. Step 5: Solve for x
    x = 777,621.70/877.91
  6. Step 6: Final answer
    x = 885.77

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Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.